Truss.



Nb. 724,500. I PATENTED APR. 7, 1903.

. A. A. RAYMOND.

TRUSS; I

APPLICATION FILED AUG. 1, 1901. RENEW-ED AUG. 22, 1902.

30 MODEL.

' Ivz-ue-nior: wilinepgses Zf' d 07: Raymond, MQ M m: NORRIS PErEns co.PMOTo-umu. wAsmNomN. u. 6.

UNITED STATES PATENT OFFICE.

ALFRED A. RAYMOND, OF CHICAGO, ILLINOIS.

TRUSS.

SPECIFICATION forming part of Letters Patent No. 724,500, dated April'7, 1903.

Application filed August 1, 1901. Renewed August 22,1902. Serial No.120,681. (No model.)

To all whom it may concern:

Be it known that I, ALFRED A. RAYMOND, a citizen of the United States,residing atjChicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Trusses, (Case No. 3,)of which the following is a full, clear, concise, and exactdescription,reference being had to the accompanying drawing, forming a part of thisspecification.

My invention relates to building, sidewalk, and similar construction,and has for its object the provision of a concrete truss possessing theadvantages of concrete construction and the strength and mechanicalproperties possessed by metal structure-Work.

The device of my invention consists of a girder which to all appearancesis completely composed of concrete or similar cemented substance, butwhich contains and incloses a tension-rod, causing this entire body ofconcrete to possess the attributes of a compression member, therebycompleting the structure of the truss.

The device of the invention is completely constructed before beingplaced in position, being distinguished in this respect from structuresformed partly of concrete or other cemented material and metal. Thecomposite girders, of metal and concrete, may readily be assembled andlocated without any adj ustment between the tension and compressionmembers thereof, this previously having been effected in the manufactureof the device.

I will explain my invention more fully by reference to the accompanyingdrawing,illustrating a girder in longitudinal section supported upontwo'uprights.

The girder a. is supported at its ends upon the uprights b b. Thisgirder contains a tension-rod c, enlarged at its ends. This enlargementis preferably effected by having the ends of the tension-rod threaded toreceive threaded caps 01 d. Inside of these caps are placed washers e e,that serve as abutments for the cement to prevent a longitudinaldisplacement of the same with respect to the tension-rod. The cement orconcrete is molded completely about the tension-trod to entirely inclosethe same. This tension-rod is bent at its middle portion somewhat in theshape of a bow, the girder being thickened at its middle portion tocorrespond to this bend in the tension-rod. One face of the.

girder is thus practically parallel with the tension-rod, having acorresponding projection at its central portion. The other face of thegirder oppositethe tension-rod is preferably flat.

Having thus described my invention, I claimas new and desire to secureby Letters Patent As an article of manufacture, a composite girderformed of concrete or similar material in which is embodied a tensionmember of iron or steel provided with enlarged ends, said. girder beingplane upon-the upper side and convex on the lower side, substantially asdescribed.

In witness whereof I hereunto subscribe my name this 30th day of July,A. D. 1901.

ALFRED A. RAYMOND.

Witnesses:

GEORGE L. CRAGG, HARVEY L. HANSON.

